Navigation and positioning systems and guide instruments for joint repair

ABSTRACT

A system and associated instruments for locating, and accurately and controllably delivering, a device to an area sufficiently near a bone defect using anatomical landmarks is provided. The instruments allow the surgeon to navigate to the area around the bone defect quickly and easily, while also facilitating proper insertion of the device. In some embodiments, the defect is located on a femur. Guide instruments having a plurality of device portals are also provided for use as standalone instruments or as accessories to the system. In addition, a protective guide sleeve is provided for the insertion of small diameter devices.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional No. 61/445,304filed Feb. 22, 2011 and entitled “Navigation and Positioning Systems andGuide Instruments for Joint Repair,” the content of which isincorporated by reference in its entirety.

FIELD

The present invention relates to tools for the surgical treatment ofjoints, and more particularly to instruments for the surgical repair andtreatment of bone joints. Even more particularly, the present inventionrelates to navigation and positioning systems, as well as guideinstruments for positioning a surgical instrument or implantable devicein an area near a bone defect of the bone to be treated using anatomicallandmarks as a reference.

BACKGROUND

Human joints, in particular the knee, hip and spine, are susceptible todegeneration from disease, trauma, and long-term repetitive use thateventually lead to pain. Knee pain, for example, is the impetus for awide majority of medical treatments and associated medical costs. Themost popular theory arising from the medical community is that knee painresults from bone-on-bone contact or inadequate cartilage cushioning.These conditions are believed to frequently result from the progressionof osteoarthritis, which is measured in terms of narrowing of the jointspace. Therefore, the severity of osteoarthritis is believed to be anindicator or precursor to joint pain. Most surgeons and medicalpractitioners thus base their treatments for pain relief on this theory.For example, the typical treatment is to administer pain medication, ormore drastically, to perform some type of joint resurfacing or jointreplacement surgery.

However, the severity of osteoarthritis, especially in the knee, hasbeen found to correlate poorly with the incidence and magnitude of kneepain. Because of this, surgeons and medical practitioners have struggledto deliver consistent, reliable pain relief to patients especially ifpreservation of the joint is desired.

Whether by external physical force, disease, or the natural agingprocess, structural damage to bone can cause injury, trauma,degeneration or erosion of otherwise healthy tissue. The resultantdamage can be characterized as a bone defect that can take the form of afissure, fracture, lesion, edema, tumor, or sclerotic hardening, forexample. Particularly in joints, the damage may not be limited to a bonedefect, and may also include cartilage loss (especially articularcartilage), tendon damage, and inflammation in the surrounding area.

Patients most often seek treatment because of pain and deterioration ofquality of life attributed to the osteoarthritis. The goal of surgicaland non-surgical treatments for osteoarthritis is to reduce or eliminatepain and restore joint function. Both non-surgical and surgicaltreatments are currently available for joint repair.

Non-surgical treatments include weight loss (for the overweightpatient), activity modification (low impact exercise), quadricepsstrengthening, patellar taping, analgesic and anti-inflammatorymedications, and with corticosteroid and/or viscosupplements. Typically,non-surgical treatments, usually involving pharmacological interventionsuch as the administration of non-steroidal anti-inflammatory drugs orinjection of hyaluronic acid-based products, are initially administeredto patients experiencing relatively less severe pain or jointcomplications. However, when non-surgical treatments prove ineffective,or for patients with severe pain or bone injury, surgical interventionis often necessary.

Surgical options include arthroscopic partial meniscectomy and loosebody removal. Most surgical treatments conventionally employ mechanicalfixation devices such as screws, plates, staples, rods, sutures, and thelike are commonly used to repair damaged bone. These fixation devicescan be implanted at, or around, the damaged region to stabilize orimmobilize the weakened area, in order to promote healing and providesupport. Injectable or fillable hardening materials such as bonecements, bone void fillers, or bone substitute materials are alsocommonly used to stabilize bone defects.

High tibial osteotomy (HTO) or total knee arthroplasty (TKA) is oftenrecommended for patients with severe pain associated withosteoarthritis, especially when other non-invasive options have failed.Both procedures have been shown to be effective in treating knee painassociated with osteoarthritis.

However, patients only elect HTO or TKA with reluctance. Both HTO andTKA are major surgical interventions and may be associated with severecomplications. HTO is a painful procedure that may require a longrecovery. TKA patients often also report the replaced knee lacks a“natural feel” and have functional limitations. Moreover, both HTO andTKA have limited durability. Accordingly, it would be desirable toprovide a medical procedure that addresses the pain associated withosteoarthritis and provides an alternative to a HTO or TKA procedure.

One of the difficulties of currently available surgical access devicesand insertion tools is the ability to target a specific area of the boneto be treated, in a fast, accurate, easy and repeatable manner.Presently, in order to treat or repair a bone defect at a joint, thesurgeon often has to take multiple steps using multiple surgical toolsin order to access, locate and treat the target defect. Even so, thesurgeon does not have a reliable instrument or system that would allowhim to repeatedly target the same site and from multiple angles orlocations outside the body. In order to perform repeated or multipleprocedures in the same defect location with the currently availabletools, additional and unnecessary time in the operating room would berequired, as well as increased risk for complications since numerousinstruments and maneuvers are at play.

Moreover, in current practice surgeons typically “eyeball” (i.e.,visually estimate) the target site on a bone to be repaired. Mostconventional targeting and location methods are relatively crude andprovide little guidance to a surgeon during the actual surgicalprocedure. Accordingly, it would be desirable to provide methods andinstruments in which the area near a bone defect can be easily locatedand provide a reference framework that can be used in a surgicalprocedure irrespective of the approach.

Accordingly, it is desirable to provide instruments that allow fast,easy, and repeatable navigation to, and positioning of surgicalinstruments or implantable devices in, an area sufficiently near a bonedefect to be treated. It is further desirable to provide instrumentsthat do not obstruct access to the working area around the target site,and allow as clear a view as possible for the clinician.

SUMMARY

The present disclosure provides instruments for locating and positioninga device in an area sufficiently near a bone defect using anatomicallandmarks. The instruments allow the surgeon to navigate to the areaaround the bone defect quickly and easily, while also facilitatingproper insertion of a device into an appropriate area near the defect.In some embodiments, the defect is located on a femur.

In one exemplary embodiment, a system for controlled delivery of adevice to a target area near a defect of a bone is provided. The systemcomprises a guide frame for holding one or more surgical access guidecomponents. Each guide component can have visual markers for determininga surgical access trajectory of the device to the target area. At leastone of the guide components includes a plurality of device portals, eachportal defining a trajectory and being configured to provide accurateand controlled delivery of the device to the target area. The systemalso includes a holder for the guide frame that secures the guide framerelative to the bone. The surgical access guide components provide a3-dimensional assessment of the surgical access trajectory of the devicein two different view planes. In one example, the visual markers areradiopaque, and are visualized through fluoroscopy. The guide componentscan include an anterior-posterior (A/P) and medial-lateral (M/L)surgical access guide accessory for use in the insertion of devices tothe target area.

In another exemplary embodiment, a guide instrument for controlleddelivery of a device to a target area near a defect of a bone isprovided. The guide instrument comprises a main body having a pluralityof device portals, each portal defining a trajectory. The main bodyfurther includes visual markers for aligning the instrument to ananatomical landmark on the bone to be treated. Each device portal isconfigured to provide accurate and controlled delivery of the device tothe target area. The guide instrument may include a handle portion formanual use, or a strap for attachment to a patient's body. The guideinstrument may also include an arm for connecting to a holder.

In still another exemplary embodiment, a protective sleeve is providedfor the insertion of a pin into cortical bone. The protective sleeveincludes an elongated body having a distal tip and a proximal handleportion. The sleeve can be cannulated for the insertion of a pin orother elongate device therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several embodiments of thedisclosure and together with the description, serve to explain theprinciples of the disclosure.

FIG. 1A is a front view of an exemplary embodiment of a hand-held guideinstrument and conceptually illustrates its use with a joint.

FIG. 1B is a perspective view of the guide instrument of FIG. 1Arelative to a joint.

FIG. 2A is a perspective view of another exemplary embodiment of a guideinstrument of the present disclosure.

FIG. 2B is a front perspective view of the guide instrument of FIG. 2Awith an optional strap.

FIG. 2C is a front view of the guide instrument of FIG. 2A andconceptually illustrates its use with a joint.

FIG. 3A is a perspective view of an exemplary embodiment of a guidecomponent.

FIG. 3B shows an exemplary embodiment of a navigation and positioningsystem with the guide component of FIG. 3A in use with a joint.

FIG. 4A is a perspective view of another exemplary embodiment of a guidecomponent of the present disclosure.

FIG. 4B shows an exemplary embodiment of a navigation and positioningsystem with the guide component of FIG. 4A in use with a joint.

FIG. 5A illustrates an exemplary use of the system of FIG. 3B with asurgical instrument on a joint.

FIG. 5B is another perspective view of the system and surgicalinstrument of FIG. 5A on the joint.

FIG. 6A is a perspective view of an exemplary embodiment of ananterior-posterior (A/P) guide accessory for use with a navigation andpositioning system of the present disclosure.

FIG. 6B is a cross-sectional view of the anterior-posterior (A/P) guideaccessory of FIG. 6A.

FIGS. 7A and 7C are cross-sectional views of exemplary embodiments of amedial-lateral (M/L) guide accessory for use with a navigation andpositioning system of the present disclosure.

FIGS. 7B and 7D are front views of the medial-lateral (M/L) guideaccessories of FIGS. 7A and 7C, respectively.

FIG. 8 shows the A/P guide accessory and the M/L guide accessory in usewith an exemplary embodiment of a navigation and positioning system ofthe present disclosure.

FIGS. 9A-9H illustrate an exemplary method of using the navigation andpositioning system with A/P and M/L accessories of FIG. 8 on a joint.

FIG. 10A is a perspective view of an exemplary embodiment of a guidesleeve of the present disclosure.

FIG. 10B is a perspective view of another exemplary embodiment of aguide sleeve of the present disclosure.

FIG. 10C is a cross-sectional view of the guide sleeve of FIG. 10B alongaxis A-A.

FIG. 11 illustrates diversion of a surgical instrument that may occurwhen used without a guide sleeve of the present disclosure.

FIGS. 12A-12C illustrate an exemplary use of the guide sleeve of thepresent disclosure.

FIGS. 13A and 13B illustrate an exemplary use of the guide sleeve with anavigation and positioning system of the present disclosure.

DESCRIPTION OF THE EMBODIMENTS

The present disclosure provides methodologies, devices and instrumentsfor diagnosing and treating joint pain to restore natural joint functionand preserving, as much as possible, the joint's articular and cartilagesurface. Treatments through the joint that violate the articular andcartilage surface often weaken the bone and have unpredictable results.Rather than focusing on treatment of pain through the joint, alternativetreatments that diagnose and treat pain at its source in the subchondralregion of a bone of a joint to relieve the pain are provided. Painassociated with joints, especially osteoarthritic joints, can becorrelated to bone defects or changes at the subchondral level ratherthan, for example, the severity of osteoarthritic progression or defectsat the articular surface level. In particular, bone defects, such asbone marrow lesions, edema, fissures, fractures, hardened bone, etc.near the joint surface lead to a mechanical disadvantage and abnormalstress distribution in the periarticular bone, which may causeinflammation and generate pain. By altering the makeup of theperiarticular bone (which may or may not be sclerotic) in relation tothe surrounding region, it is possible to change the structuralintegrity of the affected bone and restore normal healing function, thusleading to a resolution of the inflammation surrounding the defect.

Treatment of the bone by mechanical and biological means to restore thenormal physiologic stress distribution, and restore the healing balanceof the bone tissue at the subchondral level, is a more effect way oftreating pain than conventional techniques. That is, treatment can beeffectively achieved by mechanically strengthening or stabilizing thedefect, and biologically initiating or stimulating a healing response tothe defect. Methods, devices, and systems for a subchondral procedurethat achieve these goals are disclosed in co-owned U.S. Pat. No.8,062,364 entitled “OSTEOARTHRITIS TREATMENT AND DEVICE” as well as inco-owned and co-pending U.S. Patent Application Publication Nos.2011/0125156 entitled “METHOD FOR TREATING JOINT PAIN AND ASSOCIATEDINSTRUMENTS” and 2011/0125157 entitled “SUBCHONDRAL TREATMENT OF JOINTPAIN,” both of which were filed on Nov. 19, 2010, the contents of whichare incorporated by reference in their entirety. This subchondralprocedure, and its associated devices, instruments, etc. are alsomarketed under the registered trademark name of SUBCHONDROPLASTY™. TheSUBCHONDROPLASTY™ procedure is a response to a desire for an alternativeto patients facing partial or total knee replacement.

In general, the SUBCHONDROPLASTY™ or SCP™ technique is intended to bothstrengthen the bone and stimulate the bone. In SCP™, bone fractures ornon-unions are stabilized, integrated or healed, which results inreduction of a bone defect, such as a bone marrow lesion or edema. Inaddition, SCP™ restores or alters the distribution of forces in a jointto thereby relieve pain. SCP™ can be performed arthroscopically orpercutaneously to treat pain by stabilizing chronic stress fracture,resolving any chronic bone marrow lesion or edema, and preserving, asmuch as possible, the articular surfaces of the joint. SUBCHONDROPLASTY™generally comprises evaluating a joint, for example, by taking an imageof the joint, detecting the presence of one or more subchondral defects,diagnosing, which of these subchondral defects is the source of pain,and determining an extent of treatment for the subchondral defect. Thetechnique is particularly suited for treating chronic defects orinjuries, where the patient's natural healing response has not resolvedthe defect. It should be noted, however, that the technique is equallyapplicable to treatment of defects in the subchondral region of bonewhere the defect is due to an acute injury or from other violations.Several exemplary treatment modalities for SCP™ for the differentextents of treatment needed can be employed. Accordingly, a medicalpractitioner may elect to use the techniques and devices describedherein to subchondrally treat any number of bone defects, as he deemsappropriate.

Detection and identification of the relevant bone marrow lesion or bonemarrow edema (BML or BME) can be achieved by imaging, e.g., magneticresonance imaging (MRI), X-ray, manual palpation, chemical or biologicalassay, and the like. A T1-weighted MRI can be used to detect scleroticbone, for example. Another example is that a T2-weighted MRI can be usedto detect lesions, edemas, and cysts. X-ray imaging may be suitable forearly-stage as well as end-stage arthritis. From the imaging, certaindefects may be identified as the source of pain. In general, defectsthat are associated with chronic injury and chronic deficit of healingare differentiated from defects that result, e.g., from diminished bonedensity. SCP™ treatments are appropriate for a BML or BME that may becharacterized as a bone defect that is chronically unable to heal (orremodel) itself, which may cause a non-union of the bone, stress orinsufficiency fractures, and perceptible pain. Factors considered mayinclude, among other things, the nature of the defect, size of thedefect, location of the defect, etc. For example, bone defects at theedge near the articular surface of periphery of a joint may be oftenconsidered eligible for treatment due to edge-loading effects as well asthe likelihood of bone hardening at these locations. A bone defectcaused by an acute injury would generally be able to heal itself throughthe patient's own natural healing process. However, in such situationswhere the bone defect is due to an acute injury and either the defectdoes not heal on its own, or the medical practitioner decides that thepresent technique is appropriate, SCP™ treatment can be administered onacute stress fractures, BML or BME, or other subchondral defects, aspreviously mentioned.

The SCP™ treatment may continue after surgery. In particular, thepatient may be monitored for a change in pain scores, or positive changein function. For example, patients are also checked to see when they areable to perform full weight-bearing activity and when they can return tonormal activity. Of note, if needed, the SCP™ procedure can becompletely reversed in the event that a patient requires or desires ajoint replacement or other type of procedure. The SCP™ treatment mayalso be performed in conjunction with other procedures, such ascartilage resurfacing, regeneration or replacement, if desired.

A number of treatment modalities, and associated devices, instrumentsand related methods of use for performing SUBCHONDROPLASTY™ aredisclosed in the aforementioned publications. These treatment modalitiesmay be used alone or in combination.

In one treatment modality, the subchondral bone in the region of thebone marrow lesion or defect can be strengthened by introduction of ahardening material, such as a bone substitute, at the site. The bonesubstitute may be an injectable calcium phosphate ensconced in anoptimized carrier material. In SCP™, the injected material may alsoserve as a bone stimulator that reinvigorates the desired acute bonehealing activity.

For example, polymethylmethacrylate (PMMA) or calcium phosphate (CaP)cement injections can be made at the defect site. PMMA injection mayincrease the mechanical strength of the bone, allowing it to withstandgreater mechanical stresses. CaP cement injection may also increase themechanical strength of the bone, while also stimulating the localizedregion for bone fracture repair. In one embodiment, the injection can bemade parallel to the joint surface. In another embodiment, the injectioncan be made at an angle to the joint surface. In yet another embodiment,the injection can be made below a bone marrow lesion.

In another treatment modality, the subchondral bone region can bestimulated to trigger or improve the body's natural healing process. Forexample, in one embodiment of this treatment modality, one or more smallholes may be drilled at the region of the defect to increase stimulation(e.g., blood flow, cellular turnover, etc.) and initiate a healingresponse leading to bone repair. In another embodiment, after holes aredrilled an osteogenic, osteoinductive, or osteoconductive agent may beintroduced to the site. Bone graft material, for example, may be used tofill the hole. This treatment modality may create a betterload-supporting environment leading to long term healing. Electrical orheat stimulation may also be employed to stimulate the healing processof a chronically injured bone. Chemical, biochemical and/or biologicalstimulation may also be employed in SCP™. For instance, stimulation ofbone tissue in SCP™ may be enhanced via the use of cytokines and othercell signaling agents to trigger osteogenesis, chondrogenesis, and/orangiogenesis to perhaps reverse progression of osteoarthritis.

In yet another treatment modality, an implantable device may beimplanted into the subchondral bone to provide mechanical support to thedamaged or affected bone region, such as where an insufficiency fractureor stress fracture has occurred. The implant may help create a betterload distribution in the subchondral region. In the knees, the implantmay support tibio-femoral compressive loads. In addition, the implantmay mechanically integrate sclerotic bone with the surrounding healthybone tissue. The implants may be place in cancellous bone, throughsclerotic bone, or under sclerotic bone at the affected bone region. Theimplant may also be configured as a bi-cortical bone implant. In oneembodiment, one side of the implant can be anchored to the peripheralcortex to create a cantilever beam support (i.e., a portion of theimplant is inserted into bone but the second end stays outside or nearthe outer surface of the bone). The implant may be inserted using aguide wire. In one example, the implant may be inserted over a guidewire. In another example, the implant may be delivered through a guideinstrument.

The implant may further be augmented with a PMMA or CaP cementinjection, other biologic agent, or an osteoconductive, osteoinductiveand/or osteogenic agent. The augmentation material may be introducedthrough the implant, around the implant, and/or apart from the implantbut at the affected bone region, such as into the lower region of a bonemarrow lesion or below the lesion. For example, the implant may act as aportal to inject the augmentation material into the subchondral boneregion.

While each of the above-mentioned treatment modalities may beadministered independent of one another, it is contemplated that anycombination of these modalities may be applied together and in any orderso desired, depending on the severity or stage of development of thebone defect(s). Suitable implantable fixation devices for the surgicaltreatment of these altered bone regions or bone defects, especially atthe subchondral level, are disclosed in co-pending and co-owned U.S.Patent Application Publication No. 2011/0125265 entitled “IMPLANTABLEDEVICES FOR SUBCHONDRAL TREATMENT OF JOINT PAIN,” U.S. PatentApplication Publication No. 2011/0125264 entitled “IMPLANTABLE DEVICESFOR SUBCHONDRAL TREATMENT OF JOINT PAIN,” and U.S. Patent ApplicationPublication No. 2011/0125272 entitled “BONE-DERIVED IMPLANTABLE DEVICESFOR SUBCHONDRAL TREATMENT OF JOINT PAIN,” all of which were filed onNov. 19, 2010, the contents of which are herein incorporated in theirentirety by reference. These devices and instruments can be use incombination with cements or hardening materials commonly used to repairdamaged bone by their introduction into or near the site of damage,either to create a binding agent, cellular scaffold or mechanicalscaffold for immobilization, regeneration or remodeling of the bonetissue.

In general, the present disclosure provides embodiments related toinstruments and associated methods for the surgical treatment of ajoint, and particularly to a bone defect at that joint region. Morespecifically, the embodiments relate to instruments for navigating andpositioning devices into an area sufficiently near a defect of thejoint. Even more specifically, the instruments and associated methodsfor use are suitable for the repair of a femoral bone of a knee joint.These instruments and devices may be used in a manner consistent withthe subchondral procedures previously described.

In a healthy joint such as a tibio-femoral joint, the compressive loadbetween the contact bones (i.e., the femur and the tibia) is properlydistributed, thus keeping the contact stresses in the cartilage to areasonably low level. As the cartilage starts to wear out locally, thetibio-femoral contact area reduces and starts to get localized at thesite of the cartilage defect. The localization of the stresses may alsooccur due to varus or valgus deformity. Sometimes, the condition mayoccur because of osteoporosis, where bone becomes weak and is no longerable to support normal loads. This condition leads to higher localizedcontact stresses in the cartilage, and the subchondral region below thecartilage. Once the stresses reach beyond a certain threshold level, itleads to defects like bone marrow lesions and edema, and perhapsgenerates knee pain. If the problem persists, the high contact stressescan lead to sclerotic bone formation as well. The presence of scleroticbone can compromise vascularization of the local area, and also create amechanical mismatch in the bone tissue. This mismatch may start toexpedite degeneration of all parts of the joint leading to increasedlevels of osteoarthritis.

Pain associated with osteoarthritic joints can be correlated to bonedefects or changes at the subchondral level. In particular, bone defectssuch as bone marrow lesions, edema, fissures, fractures, etc. near thejoint surface lead to abnormal stress distribution in the periarticularbone, which may or may not cause inflammation and generate pain. Byaltering the makeup of the periarticular bone (which may or may not besclerotic) in relation to the surrounding region, it is possible tochange the structural integrity of the affected bone, leading to aresolution of the inflammation. Treatment of the bone in an effort toalter the structural makeup of the affected periarticular bone leads toreduced inflammation and pain has proven to be successful. Over time,normal physiologic stress distribution can be achieved, and mechanicalcongruity restored, thereby resulting in healing of the inflammation andreduction or elimination of pain.

As previously mentioned, there is a need for surgical instruments thatallow fast, easy, and repeatable navigation to, and proper positioningof surgical instruments or implantable devices into, a generalized areasufficiently near a bone defect to be treated. Applicants havediscovered instruments that are particularly suitable for accessingcertain areas of the bone within the range of about 2-15 mm from thebone surface, and more commonly about 5-10 mm from the bone surface,such as the articular surface or the subchondral bone area. Theseinstruments are also particularly suited to aid in the insertion oftools, devices, implants, etc. in a predetermined angular orientationwith respect to the top surface of the bone to be treated (e.g., in aparallel or angled orientation). Accordingly, the present disclosureprovides suitable instruments and associated methods for the surgicaltreatment of these bone defects, especially at the subchondral levelnear sclerotic bone.

Turning now to the drawings, FIGS. 1A and 1B show an exemplaryembodiment of a guide instrument 20 of the present disclosure inrelation to a knee joint 2. The guide instrument 20 may be configured toprovide simple, repeatable targeting of a local target area near a bonedefect in a bone of the joint 2. In addition, the guide instrument 20allows navigation and access to a target area from various angles, orlocations, outside the joint 2. In the drawings and embodimentsdescribed, the bone to be treated may be a femur 4 of the knee joint 2,with the condyles 6 and adjacent tibia 8 clearly identifiable from thedrawings. For ease of illustration, the representative bones of thejoint 2 (femur 4, tibia 8) are shown clean and stripped of flesh andskin (i.e., the bone is shown without surrounding tissues). However, itis understood that the bone may be any other kind of bone joint, such asa hip joint or shoulder joint.

The guide instrument 20 may include a main body 22 having a plurality ofdevice portals 24. Each of the device portals 24 may be sized to allow adevice to be inserted therethrough at a desired angle toward the bonedefect to be treated. For instance, the portals 24 may be configuredwith an angular trajectory that is different than a neighboring portal24, such that each portal 24 of the array of portals 24 on the main body22 may allow a different angular trajectory or approach to the targetsite to be treated. These device portals 24 act as positioning guidesfor inserting a device, such as a pin or other tool or implant, to thebone to be treated. Each of the device portals 24 has a predetermineddistance and spatial relationship relative to the other portals. Theportals 24 serve as spatial reference or orientation or location markersfor the clinician. Moreover, the device portals 24 are configured toprovide accurate and controlled delivery of a device to the target site.

As described and shown throughout the disclosure, the device inreference may be a pin. However, the term “device” as used herein isintended to refer generally to any number of implantable devices, toolsor instruments suitable for bone treatment and/or repair. As will bedescribed in more detail below, the device may be an implantable device,an insertion tool, a drill bit, a wire, an injection needle, a catheter,or any other surgical instrument. Accordingly, the guide instrument 20may be used to provide quick, easy, and repeatable targeting and accessof an area at or near a bone defect by a number of instruments orimplants that can perform any variety of treatment functions.

In order to ensure that the guide instrument 20 is positioned properly,the main body 22 may include one or more fluoroscopic visualizationmarkers 26 that may be used to orient the guide instrument 20 relativeto the bone to be treated. In the present example, the bone may be thefemur 4 of a knee joint 2, and the fluoroscopic markers 26 may be linedup to anatomical landmarks on the femur 4 such as the condyles 6. Theinstrument 20 may also be configured for use fluoroscopically to locatethe area near the defect visually from the cartilage surface.

In one embodiment, the guide instrument 20 may be provided with a handleportion 28 as shown in FIGS. 1A and 1B. The handle portion may beconfigured with adequate clearance to keep the user's or clinician'shands out of the C-arm shot (during fluoroscopic visualization). In thisparticular example, the guide instrument 20 may be configured as ahand-held instrument capable of easy maneuvering and repositioningduring surgery.

In another embodiment, the guide instrument 20 may have an attachmentmechanism for added security. As shown in FIGS. 2A and 2C, the guideinstrument 20 may have cutout side portions 30 on the main body 22. Aspindle 32, or other side bar or tab, may be provided in the cutout sideportions 30, for receiving a strap 34, band or belt, as shown in FIG.2B. The strap 34 may be adjustable, and detachable. For example, thestrap may be formed of an elastic material such as an elastic band, orthe strap 34 may include an adhesive material such as a skin-adhesiveglue strip. In other examples, the strap may include a Velcro fasteneror other detachable fastener. The strap 34 allows the guide instrument20 to be held onto the patient's leg or thigh during use. In the presentembodiment, the fluoroscopic markers may be embedded within the mainbody 22 of the guide instrument 20.

It is contemplated that, although the guide instrument 20 is shown asbeing used for treatment of a femur 4, the guide instrument 20 may workequally as well with the tibia 8. In addition, it is understood that theguide instrument 20 may be used in the surgical treatment of otherjoints of the human body.

FIGS. 3A, 3B, 4A and 4B illustrate exemplary embodiments of a guidecomponent 120 configured for use in a navigation and positioning system100 of the present disclosure. The navigation and positioning system 100and guide instruments 20 of the present disclosure enable repeatable,controlled delivery of a device to a target area that sufficientlycoincides at or near a bone defect in the subchondral level of the boneto be treated. In most cases, diagnosis and identification of a defector defects that are consistent with the ones described for use with thepresent instruments may be made by magnetic resonance imaging (MRI).However, it is also possible by simply palpating the patient (i.e.,through manual examination) to identify an injury or defect suitable fortreatment by the present instruments.

The navigation and positioning instrument 100 may comprise at least twosubcomponents: a guide component 120, and a holder 110 for the guidecomponent 110. The guide component 120 may have a generally rectangularmain body, similar to the embodiment shown in FIG. 3A, or the guidecomponent 120 may have a generally round main body 122, similar to theembodiment shown in FIG. 4A. Of course, other geometries are availablefor the main body 122, including oval, trapezoidal, etc.

As with guide instrument 20, the main body 122 of guide component 120may include a plurality of device portals 124. Each of the deviceportals 124 may provide a different angular approach to the bone defectto be treated. Fluoroscopic markers may be embedded within the main body122 to assist with visual alignment of the guide component against thejoint 2.

The main body 122 of the guide component 120 may extend into an arm, orrail, component 130 that terminates at a free end 132 having a notchedregion 134. The rail component 130 may be configured to releasablyattach to the holder 110 of the system 100. The holder 110 may be of thetype that can be positioned or stabilized against the tibia 8 of thejoint 2. FIGS. 3B and 4B show the embodiments of the guide component 120of FIGS. 3A and 4A, respectively, attached to such a holder 110. FIGS.5A and 5B illustrate a manner of using the navigation and positioningsystem 100 with attached guide component 120 to direct a pin 10 into abone of a joint 2 to be treated. The pin 10 may be inserted through oneof the device portals 124 of the guide component 120 and directedthrough the angular approach towards an identified bone defect of thefemur 4. Once the pin 10 is inserted into the femur 4 as shown in FIG.5B, if desired the guide component 120 may be detached from the holder110 and removed from the surgical site without disturbing itssurroundings.

In one embodiment, the pin 10 may be used as a fluoroscopic marker. Inthis example, the pin 10 would be placed into the guide component 120but would not puncture the skin, tissue or bone. Instead, the pin 10 maybe moved relative to its original position and viewed fluoroscopically(i.e., after C-arm shots). This technique would allow the pin 10 to bepre-adjusted prior to its insertion into bone.

FIGS. 6A, 6B and 7A-7D illustrate other guide accessories that may beused with a navigation and positioning system 100 of the presentdisclosure. FIGS. 6A and 6B show a guide accessory 150 configured foranterior-posterior (A/P) visualization, while FIGS. 7A-7D show a guideaccessory 160 configured for medial-lateral (M/L) visualization. FIG. 8illustrates a navigation and positioning system 100 having A/P guideaccessory and M/L guide accessory attached thereto. The navigation andposition system 100 may include a holder 110, and a pair of railcomponents 140 held by the holder 110 and form a reference or guideframe that provides a framework and guide for positioning devices intothe bone 8 to be treated. The rail components 140 may include deviceportals 144 at various angular approaches. Further, as with the otherguide components and instruments of the present disclosure, the railcomponents 140 may include fluoroscopic markers 148 that assist inproper alignment of the system 100 under fluoroscopy.

Turning back to the specific guide accessories of the presentdisclosure, as shown in FIG. 6A, the A/P guide accessory 150 maycomprise a main body 152 having an attachment mechanism 158 forattaching to the rail component 140 of the system 100. The attachmentmechanism could be, for instance, a dovetail connection. The A/P guideaccessory 150 may include fluoroscopic markers for alignment relative toanatomic landmarks on the bone to be treated. As shown in greater detailin the cross-sectional view of FIG. 6B, radiopaque or fluoroscopicmarkers 154 may be provided inside the A/P guide accessory 150. Theseinternal markers 154 can be viewed under a C-arm or other similarvisualization device, and used to aid the clinician with the alignmentof the accessory 150 relative to the bone to be treated. Consequently,the markers 154 of the A/P accessory 150 also allows the clinician toassess the projected insertion pathway, as will be described in moredetail below.

The M/L guide accessories 160 of FIGS. 7A-7D may also comprise a mainbody 162 including a plurality of device portals 164, 166 and anattachment mechanism (not shown) for attachment to the rail components140 of the system 100, as shown in FIG. 8. The attachment mechanism maybe a dovetail connection, for instance, or any other quick-releasedetachable connection. Like A/P guide accessory 150, the M/L guideaccessory 160 may be provided with radiopaque or fluoroscopic markersthat aid in the alignment of the accessory 160 relative to the bone tobe treated. FIGS. 7B and 7D illustrate a front view of a left version160A and a right version 160B, respectively, of the M/L guideaccessories of the present disclosure. Each of the M/L accessories 160A,160B can include external visual markers, such as etchings 168A, forexample. Other types of visual markers may also be employed, such asgeometric representations like surface projections. These externalvisual markers 168A correspond to internal markers 168B, as shown incross-sectional view in FIGS. 7A and 7C corresponding to left M/Laccessory of FIG. 7B and right M/L accessory of FIG. 7D, respectively.Like visual markers 154, these internal markers 168B may be radiopaqueor fluoroscopic in nature so that they show up under a C-arm.

Both the A/P and M/L guide accessories of the present disclosure areconfigured to serve multiple functions. These guide accessories 150, 160may be provided to the user as a set of varying sizes, or heights. Forexample, each of the accessories may be provided in 15 mm, 20 mm, and 25mm height versions. One role the guide accessories play with the system100 of the present disclosure is a size gauge. In addition, these sameguide accessories also serve as a reference for the insertion of adevice toward the defect site. These functions, of course, are inaddition to the role these guide accessories play in the positioning ofthe system 100 relative to anatomical markers.

In one exemplary manner of using the guide accessories 150, 160A, 160Bwith the navigation and positioning system 100 as a size gauge, theclinician would select one sized guide accessory from a set ofdifferently sized accessories, such as for example, a medium sized A/Pguide accessory 150. Comparing the fluoroscopic markers 154 toanatomical markers, the user can make a determination that the selectedmedium sized A/P guide accessory 150, is too low (i.e., the markers 154are visualized going into the joint space), too high (i.e., the markers154 do not overlap the defect site), or just right. If the accessory 150is too low, the user can then swap out the medium sized A/P guideaccessory 150 for a larger or taller sized A/P guide accessory 150. Ifthe accessory 150 is too high, the user can likewise swap out the mediumsized A/P guide accessory 150 for a smaller or shorter sized A/P guideaccessory 150. The A/P guide accessories and M/L guide accessories maybe color coded or visually marked so that it is convenient for the userto determine which guide accessories correlate. For example, a 20 mm A/Pguide accessory 150 would have the same color coding or marking as a 20mm M/L guide accessory 160, while a 15 mm A/P guide accessory 150 wouldhave the same color coding or marking as the 15 mm M/L guide accessory160. In all these circumstances, the navigation and positioning system100 including the holder 110 and the rail components 140 remainsstationary, while the user can interchange differently sized guideaccessories 150, 160A, 160B until the appropriate components areselected.

After the appropriately sized guide accessories are attached to the railcomponents 140 of the navigation and positioning system 100, the usermay select from one of many surgical access trajectories or pathwaysoffered by the M/L guide accessory 160A, 160B. To do this, the user mayconsider how the radiopaque or fluoroscopic markers relate to anatomicallandmarks of the joint to be repaired. For example, the user may look atthe joint under a medial lateral fluoroscopic view and determine how theinternal markers 168B of M/L guide accessory 160 correspond to theanatomy of the joint. The clinician may determine that an appropriateinsertion pathway would be to insert a pin 10 between two of the markers168B. The clinician would be able to determine which portal 164, 166 touse for inserting the pin 10 from a normal view of the guide accessorysince the external visual markers 168A correspond to the internalmarkers 168B that were viewed under fluoroscopy. Thus, the pin 10 couldbe inserted into the appropriate portal 164, 166 using external visualmarkers 168A as a visual reference, and based on correspondingfluoroscopic representations of the internal markers 168B. This exampleillustrates how the M/L guide accessories 160 can serve as a referencefor the insertion of a device to the defect site.

FIGS. 9A-9H represent an exemplary method of using the navigation andpositioning system 100 of FIG. 8 to access a femoral defect, i.e., totarget a subchondral defect in a femur 4 of a bone joint 2. First, aholder 110 with attached rail components 140 is secured to a first bone,which in this case is the tibia 8. If the method is being performedunder fluoroscopy, the fluoroscope may be rotated into a trueanterior-posterior (A/P) view. As shown and in use, the leg should be ina fully extended position.

Next, the A/P guide accessory 150 may be attached to the rail component140 via a dovetail connection, on the operative side of the pair of railcomponents 140, as shown in FIG. 9A. As previously discussed, the A/Pguide accessories 150 may be provided as a set of varying sizes, orheights, such as 15 mm, 20 mm, 25 mm, etc. The user may be able toselect the accessory having the correct height or angle to provide thenecessary pathway to the defect. For example, a 20 mm version of the A/Pguide accessory 150 may be selected and attached to the rail component140. Under fluoroscopic imaging, the user may be able to determine ifthe radiopaque markers 154 of the A/P guide accessory 150 align with thedesired insertion trajectory into the femoral condyle. As shown in FIG.9A, the 20 mm version of the A/P guide accessory 150 having height h₁ istoo low. The radiopaque markers 154 when viewed under fluoroscopyproject a trajectory into the joint space, not toward the defect. So,the user may remove the accessory and replace with a larger (e.g., 25mm) A/P femoral guide accessory 150 having a height h₂ that isappropriate, as further shown in FIG. 9B. The markers 154 of the largerA/P guide accessory 150 project an appropriate trajectory path towardthe defect site.

After the appropriately sized A/P guide accessory 150 has been selectedand attached to the rail component 140, the corresponding M/L guideaccessory 160 may be attached to the same rail component 140 at itsposterior end, as shown in FIG. 9C. Rotating the fluoroscope into alateral view, a lateral fluoroscopic image may be taken of the M/L guideaccessory 160. Based on pre-operative determination of theanterior-posterior depth of the defect, the user may determine theappropriate surgical access trajectory to reach the defect. The externalvisual markers 168A on the M/L guide accessory 160 and shown in FIG. 9Cmay be used as a reference to locate the appropriate portal 164, 166 forsurgical access to the defect. As previously described, these externalvisual markers 168A correspond to internal radiopaque markers 168B thathave been identified under fluoroscopy.

Once the M/L guide accessory 160 is secured to the rail component 140and the surgical access trajectory selected, a device such as a sharp orbladed pin 10 may be placed through the desired device portal 164, 166of the M/L guide accessory 160. Use of either parallel or angledapproaches may be based on the user's preference, as illustrated inFIGS. 9D and 9E. In one embodiment, each one of the series of portals164 may be provided at an angle, while each one of the series of portals166 may be provided with a 0 degree angle. In FIG. 9D, portal 166 may beemployed for a parallel approach. In FIG. 9E, portal 164 may be employedfor an angled approach, such as at a 15 degree angle, to the defect.

As shown in FIG. 9F, the trajectory of pin 10 into the bone 4corresponds to the radiopaque markers 154 in the A/P guide accessory150. In FIG. 9F, it should be noted that the markers 154 of A/P guideaccessory 150 are being represented as fluoroscopically visualizedlaying over, or overlapping with, the pin 10 that is situated behind theA/P guide accessory 150. The pin 10 itself extends through M/L guideaccessory 160 only, and does not extend into the A/P guide accessory150, as can be seen from a different view of the same system 100 in FIG.9C. Pin placement may be verified using fluoroscopic visualization inthe A/P and M/L views. This would be achieved, for example, by rotatingthe fluoroscope into an anterior-posterior view, removing the A/Pfemoral guide accessory 150, and then under fluoroscopic imaging,confirming the pin 10 trajectory. Once confirmed, the pin may beinserted to the desired depth. Radiopaque markings on pin 10 may be usedto indicate A/P depth zones. Using a cannulated drill or otherinstrument, the pin 10 may be advanced to the desired depth underfluoroscopic guidance.

After the pin 10 has been properly inserted, the A/P and M/L guideaccessories 150, 160 may be removed from the rail component 140, asshown in FIG. 9G. If so desired, a final pin placement verification canbe made under fluoroscopy. Once verified, the entire system 100 may beremoved such that only the pin 10 remains, as shown in FIG. 9H. Byproviding a system 100 that allows A/P visualization (via the A/Pfluoroscopic guide) along with M/L visualization (via the M/Lfluoroscopic guide) and M/L pin placement, the clinician is able to geta 3-dimensional trajectory using two different guides, both of whichcould have fluoroscopic markers. These interchangeable guide accessories150, 160 enable the user to customize the system 100 to the particularanatomical requirements of the joint, while also allowing a true 3Dtrajectory in two different view planes oblique or orthogonal to oneanother, that can be seen using x-ray or fluoroscopic imaging.

While the present embodiment describes guide accessories that enablevisualization under fluoroscopy or x-ray using fluoroscopic orradiopaque markers, it is contemplated that the same concepts may beapplied to a system employing guide accessories that utilize lasertechnology to transpose laser markings or visual cues onto the patient'sskin or tissue, or to guide accessories that employ probes or otherphysical markers that point onto the patient's anatomy. In other words,the present disclosure is not intended to be limited to fluoroscopic orradiopaque markers to ascertain the surgical access trajectory in twodifferent planes oblique or orthogonal to one another. Rather, theconcept of providing multiple components that can be easily interchangedonto a stationary guide frame attached to the patient and which allowvisualization can be carried out using other forms of visualizationtechniques, such as with laser technology, or physically such as with apointer or probe.

FIGS. 10A-10C show embodiments of a guide sleeve 60 suitable for usewith any of the navigation and positioning systems 100 or guideinstruments 20 of the present disclosure. The guide sleeve 60 may have aproximal head portion 64 for holding the sleeve 60, and a distal tip 62.The distal tip 62 may be configured to rest on, or just break thesurface of, cortical bone. The proximal head portion 64 may beconfigured to be manually held or secured to a stabilizing device. FIG.10B illustrates an embodiment of the guide sleeve 60 with a knurled head66. As the cross-sectional view shows in FIG. 10C, the guide sleeve 60is cannulated to allow a device such as a pin 10, wire, drill bit, etc.to be protected while being inserted into bone tissue.

Presently, small diameter pins 10 or wires that are driven into corticalbone tend to skive off and redirected from a desired trajectory into thebone. The skin, fat, muscles, and hard bone forces the pin 10 in thepath of least resistance. The moment arm created is sufficiently largeas to bend the pin from its original path. This skiving effect isconceptually shown in FIG. 11. To avoid this skiving effect, smalldiameter pins 10 may be inserted with a protective sleeve such as theguide sleeve 60 of the present disclosure.

FIGS. 12A-12C represent a method of using the guide sleeve 60 to inserta small diameter pin 10 into cortical bone. First, as shown in FIG. 12A,a guide sleeve 60 may be placed such that the tip 62 enters through thepatient's skin, fat, and muscle and rests against the cortical bonesurface. In the illustration, the bone may be a tibia 8. Then, a pin 10can be driven through the guide sleeve 60 and into the cortical shell ofthe tibia 8. As the pin 10 continues to be drilled into the bone, thepin 10 is directed straight along its desired pathway. The guide sleeve60 allows the pin to be able to bypass the skin, fat and muscles. Thepin 10 can therefore be driven straight through the cortical bone byexposing only a very short length of the pin 10 during the insertionprocess. The shortened length of pin 10 allows for a small moment arm tobe created, and is therefore much stiffer while passing through thecortical bone.

The guide sleeve 60 may also be used in conjunction with the navigationand positioning systems 100 or guide instruments 20 of the presentdisclosure. For example, as shown in FIGS. 13A and 13B, the guide sleeve60 may be held by or passed through any of the device portals 24, 124,144 of the navigation and positioning systems 100 or guide instruments20 prior to insertion of the pin 10. The guide sleeve 60 could also beheld manually as the pin 10 is drilled into bone.

The navigation and positioning system 100 and the guide instruments 20of the present disclosure provide several advantages, including simple,repeatable targeting of an area near a defect in a bone for percutaneoustreatment of that defect. The defect could be, for example, a bonemarrow lesion in the subchondral region of the bone to be treated. Thecircular navigation and positioning system 100 serves as a 3-dimensionalreference system to position devices towards the area of the defect,while the various device portals 144 allow for percutaneous targeting ofthe area near the defect. In addition, the guide instruments 20 allowfor repeatable targeting of the area near the defect in the range ofabout 5-10 mm below the articular surface or in the subchondral level ofthe bone.

The navigation and positioning system 100 and guide instruments 20 ofthe present disclosure are suitable for use where it is desirable totreat a local area specific to a defect of a bone using a percutaneousapproach. As discussed, the system 100 and instruments 20 may be usedwith a C-arm in conjunction with an MRI template system for identifyingthe area to be treated, and for aligning or positioning devices intendedto be introduced to that area. The system 100 and instruments 20 arealigned to the bone by reference to the bone's own natural geometry andtakes into account anterior-posterior (A/P) as well as verticalplacement.

A number of treatment modalities, and associated devices, instrumentsand related methods of use can be employed using the navigation andpositioning system 100 and guide instruments 20 just described. In onetreatment modality, the target area local to the defect can bestrengthened by introduction of a hardening material at the site. Forexample, polymethylmethacrylate (PMMA) or calcium phosphate (CaP) cementinjections can be made at the defect site. PMMA injection may increasethe mechanical strength of the bone, allowing it to withstand greatermechanical stresses. CaP cement injection may also increase themechanical strength of the bone, while also stimulating the localizedregion for bone fracture repair. In one embodiment, the injection can bemade parallel to the joint surface. In another embodiment, the injectioncan be made at an angle to the joint surface. In yet another embodiment,the injection can be made below the target area. In another embodiment,there could be provided the combination of an implant or device insertedparallel to the joint surface and cement injection can be made at anangle below the target area.

In another treatment modality, the target area can be stimulated toimprove the body's natural healing process. For example, in oneembodiment of this treatment modality, small holes may be drilled at theregion of the defect to increase stimulation (e.g., blood flow, cellularturnover, etc.) and initial bone repair. However, it is understood thatholes may be created using any number of cavity creation tools, otherthan drill bits, such as with a tamp, series of cannulas, or other knowntools. In another embodiment, after holes are drilled an osteogenic,osteoinductive, or osteoconductive agent may be introduced to the site.Bone graft material, for example, may be used to fill the hole. Thistreatment modality may create a better load supporting environmentleading to long term healing.

In yet another treatment modality, an implantable device may beimplanted into target area to provide mechanical support to the damagedor affected bone region, such as where an insufficiency fracture hasoccurred. The implant may help create a better load distribution in thesubchondral region. In the knees, the implant may support tibio-femoralcompressive loads. In addition, the implant may mechanically integratesclerotic bone with the surrounding healthy bone tissue. The process ofcompacting bone tissue at the target site may be a treatment modality byitself. Since the navigation and positioning system 100 and guideinstruments 20 of the present disclosure provide the advantage ofcontrolled and repeatable access to an area near a defect from a varietyof angles or trajectories, the navigation and positioning system 100 andguide instruments 20 may be used to compact bone tissue at the targetarea from multiple approaches, or angles, creating a starburst-likepattern.

The system 100 and instruments 20 of the present disclosure are intendedto work with image mapping or template systems. The device portalsshould be configured with trajectories that can correlate to thetemplate system. In this manner, the insertion of the device through thesystem 100 or instrument 20 and to the defect area can correlate withthe mapped image of the defect. Such mapping may be done by way of, forexample, MRI images that can be either pre-operative or intra-operative,for instance.

While each of the above-mentioned treatment modalities may beadministered independent of one another, it is contemplated that anycombination of these modalities may be applied together and in any orderso desired, depending on the severity or stage of development of thebone defect(s).

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of thedisclosure provided herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the disclosure being indicated by the following claims.

1. A system for controlled delivery of a device to a target area near adefect of a bone, comprising: a guide frame for holding one or moresurgical access guide components, each guide component having visualmarkers for determining a surgical access trajectory of the device tothe target area, at least one of the guide components including aplurality of device portals, each portal defining a trajectory and beingconfigured to provide accurate and controlled delivery of the device tothe target area; and a holder for the guide frame, the holder securingthe guide frame relative to the bone; wherein the surgical access guidecomponents provide a 3-dimensional assessment of the surgical accesstrajectory of the device in two different view planes.
 2. The system ofclaim 1, wherein the visual markers are radiopaque.
 3. The system ofclaim 1, wherein the guide frame is circular.
 4. The system of claim 1,wherein the guide frame comprises a pair of circular rail arms.
 5. Thesystem of claim 4, wherein the circular rail arms include radiopaquemarkers for aligning the guide frame relative to an anatomical landmarkof the bone.
 6. The system of claim 1, wherein at least one guidecomponent is configured as an anterior-posterior visual guide component.7. The system of claim 1, wherein at least one guide component isconfigured as a medial-lateral visual guide component.
 8. The system ofclaim 7, wherein the device portals are provided on the medial-lateralvisual guide component.
 9. The system of claim 1, wherein the one ormore surgical access guide components are releasably attachable to theguide frame.
 10. The system of claim 1, wherein the holder is releasablyattachable to the guide frame.
 11. The system of claim 1, wherein thedevice is an implantable device.
 12. The system of claim 1, wherein thedevice is an insertion tool, drill, pin, wire, injection needle, orcatheter.
 13. The system of claim 1, wherein the bone is a femur.
 14. Aguide instrument for controlled delivery of a device to a target areanear a defect of a bone, comprising: a main body having a plurality ofdevice portals, each portal defining a trajectory, the main body furtherincluding visual markers for aligning the instrument to an anatomicallandmark on the bone to be treated; wherein each device portal isconfigured to provide accurate and controlled delivery of the device tothe target area.
 15. The instrument of claim 14, wherein each deviceportal has a different angular trajectory than an adjacent deviceportal.
 16. The instrument of claim 14, wherein the visual markers arefluoroscopic markers.
 17. The instrument of claim 14, further includinga handle portion.
 18. The instrument of claim 14, further including anarm that connects to a holder.
 19. The instrument of claim 14, furtherincluding a strap for securing to a patient's body.
 20. The instrumentof claim 14, wherein the visual markers are embedded within the mainbody of the instrument.